g pPlane25
v -50 0 50
v -50 0 -50
v 50 0 -50
v 50 0 50
vt 0 0
vt 0 1
vt 1 1
vt 1 0
vn -0 1 0
vn -0 1 0
vn -0 1 0
vn -0 1 0
g pPlane25_0
f 3/3/3 2/2/2 1/1/1
f 4/4/4 3/3/3 1/1/1